Mdevices Surgical Marking Pen Fine tip with 0.5mm line width with a ruler. Sterilized, Box of 25 (SU010121)m devices Surgical Skin Marker Pens are a specific type of pen used to outline mark the surgical incision site on the skin. The pen is latex free, noncytotoxic and has been tested for biological safety in compliance with ISO10993 for skin irritation and sensitization. The marking agent is based on gentian violet, a traditional marking agent which has wide tolerance within the population. Surgical Skin Marker Pens are available in regular and fine tip